Footwear including a self-adjusting midsole

ABSTRACT

An article of footwear including an outsole having a plurality of first traction members extending from the outsole and defining a plurality of openings. A plurality of second traction members extend through the openings in the outsole and are configured to move between an extended position, where the second traction members are fully extended in the openings, and a retracted position, where the second traction members are at least partially retracted within the openings. A compressible member is positioned adjacent to the plurality of second traction members and is configured to compress when the second traction members move to the retracted position.

BACKGROUND OF THE INVENTION

Running and walking generate stress on a person's body, especially theirfeet, from the repeated impact of their feet with the ground. Off-roadrunning, where the ground's softer and more forgiving than pavement,lessens the impact on the body. Trail running is gaining popularity forthis and other reasons.

Different terrains require different footwear traction. For example,off-road runners often encounter loose gravel or mud. Trail shoes are,for the most part, quite similar in construction to road running shoes.However, off-road running shoes are made to be more durable than roadshoes to endure the roughness of the terrain, i.e., rocks and unevenground. Also, off-road running shoes typically have cleats or cleat-likesurfaces that project downwardly from the bottom surface of the shoe toimprove traction between the shoe and the ground. The longer the cleats,the better grip a shoe will have with the ground. Road shoes, on theother hand, have shorter cleats or no cleats to improve surface contactbetween the bottom of the shoe and the ground since road running is doneon hard surfaces such as roads, sidewalks and other paved surfaces.

The structure and support of a shoe depends on the terrain or surfacethat the shoe will be used on. For example, shoes that are primarilyused for running on trails will have different traction than shoes usedfor running on harder surfaces such as pavement. For this reason,runners that run on both off-road and on-road surfaces typically have atleast one pair of shoes for road running and at least one other pair ofshoes for off-road running. Having multiple pairs of shoes is expensive.Also if a runner plans to run on a coarse having both on-road andoff-road surfaces, the runner must decide which of their pairs of shoeswill work best for both surfaces, often sacrificing traction on one ofthe surfaces.

BRIEF SUMMARY

The present footwear includes a midsole that adjusts traction todifferent terrains. By providing self-adjusting traction, the samefootwear can be used on different terrains without sacrificing supportor traction.

Specifically, the present footwear includes an outsole having aplurality of first traction members extending from the outsole anddefining a plurality of openings. A plurality of second traction membersextend through the openings in the outsole and are configured to movebetween an extended position, where the second traction members arefully extended in the openings, and a retracted position, where thesecond traction members are at least partially retracted within theopenings. A compressible member is positioned adjacent to the pluralityof second traction members and is configured to compress when the secondtraction members move to the retracted position.

In another embodiment, the present footwear includes an outsoleincluding traction components located on a perimeter of the outsole forproviding traction on an underlying surface, and a plurality of openingson a central portion of the outsole. A plurality of adjustable lugsextend through and are movable within the openings. An adjustment memberis operatively connected to the adjustable lugs for extending orretracting the lugs based on the hardness of the underlying surface.

In a further embodiment, the present footwear includes an outsoleincluding a plurality of fixed lugs integrally formed on at least aportion of a perimeter of a first side of the outsole where the outsoledefines a plurality of openings located at least partially within theplurality of lugs. A plurality of adjustable lugs extend through theopenings where the adjustable lugs are movable between an extendedposition and a retracted position. A compressible member is positionedadjacent to the plurality of adjustable lugs on a second, opposing sideof the outsole. The plurality of adjustable lugs are in the extendedposition when the compressible member is not compressed, and theadjustable lugs being in a retracted position when the compressiblemember is compressed.

DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a bottom perspective view of footwear including theself-adjusting midsole.

FIG. 2 is an exploded perspective view showing the self-adjustingmidsole and the outsole.

FIG. 3 is a top view of the outsole.

FIG. 4 is a cross-section view of the self-adjusting midsole and theoutsole taken substantially along the line 4-4 shown in FIG. 1 where theadjustable lugs are in the extended position.

FIG. 5 shows the cross-section view of FIG. 4 where the footwear iscontacting a rough terrain and the adjustable lugs retract and compressthe compressible member.

DETAILED DESCRIPTION

Referring now to FIGS. 1-3, an article of footwear including a midsolethat adjusts to the hardness or softness of different terrains toprovide better traction for users.

The article of footwear generally designated as reference number 10,includes a midsole 11 that is removably attached to an outsole 12 formedof a relatively durable material that is molded to have a particulardesign or shape such as the shape shown in FIG. 2. The outsole 12includes a ground-contacting side or bottom surface 14 having aplurality of relatively rigid, fixed traction members or lugs 16integrally formed with the bottom surface 14 of the outsole andextending about at least a portion of the outer perimeter 18 of thebottom surface. The bottom surface 14 of the outsole also includes atread pattern 20 for enhancing the traction of the outsole. The treadpattern 20 may be any suitable tread pattern or combination of treadpatterns. The outsole 12 also defines a plurality of openings or throughholes 22 that are described in more detail below. The upper or topsurface 24 of the outsole, which is opposite to the bottom surface 14,defines a recess or recessed area 26 in the toe-portion or front portionof the article of footwear.

The outsole 12 is preferably made of two components—a base 28 and anouter layer 30. The base 28 is preferably molded using a foam materialor foam-based material, such as ethylene vinyl acetate (EVA), having adesignated hardness that is determined based on the use of the footwear.In an embodiment, the hardness or hardness value of the base 28 ispreferably 54 to 60 asker C but it is contemplated that the base mayhave any suitable hardness value. The ground-contacting portion of thebase 28 is made of an abrasion resistant material. In anotherembodiment, an abrasion resistant material or coating is applied to thebase 28. The outer layer 30 is preferably made of a solid rubber but canalso be made with blown rubber, a combination of EVA and rubber blendedcompounds, rubber compounds or other suitable materials. The outer layer30 is attached to the base 28 by molding, adhesive or any other suitableattachment method. The hardness of the outer layer 30 is 58 to 62 shoreA but may be any suitable hardness value. It should be appreciated thatthe base 28 and the outer layer 30 may also be integrally formed to makethe outsole 12.

An adjustment member 32 is positioned in the recess 26 defined by theupper surface 24 of the outsole 12 and includes a plurality ofadjustable traction members or adjustable lugs 34 that are integrallyformed with the adjustment member 32 and project downwardly from abottom surface 36 of the adjustment member. The adjustable lugs 34 havea size, shape and pattern that allow the lugs to be inserted through theopenings 22 defined by the outsole 12. When the adjustment member 32 ispositioned in the recessed area or recess 26 of the outsole 12, theadjustable lugs 34 extend through the through holes 22 and are adjacentto the fixed lugs 16 on the outsole 12 to form part of the groundcontacting side or bottom surface 14 of the outsole. As shown in FIG. 1,the adjustable lugs 34 of the adjustment member 32 are positioned withinthe fixed lugs 16 of the outsole 12 so that the fixed lugs enclose atleast a portion of the adjustable lugs. It should be appreciated thatthe fixed lugs 16 and the adjustable lugs 34 may be on any portion ofthe outsole 12.

The adjustment member 32 is preferably made of rubber but also may bemade with rubber compounds, a foam or foam-based material such as EVA,or any other suitable material or combination of materials. In anembodiment, the adjustment member 32 is made of a material having ahardness of 58 to 62 shore A. Preferably, the adjustment member 32 ismade of a material having a hardness that is greater than the hardnessof the material forming the base 28 to provide sufficient cushion andcomfort to a user. As shown in FIGS. 3 and 4, the adjustable lugs 34 onthe adjustment member 32 have a size and shape that provides sufficientclearance between the outside surface of each of the adjustable lugs andthe inside surface of the through holes 22 to allow the adjustable lugsto move relative to the through holes.

An upper portion 38 of the adjustment member 32 has a thickness thatcorresponds to the depth of the recessed area 26 defined in the uppersurface 24 of the outsole 12 to allow the upper surface 40 of theadjustment member 32 to be substantially flush with the upper surface 24of the outsole 12 after the adjustment member 32 is positioned in therecessed area. This minimizes any bumps or unevenness on the uppersurface of the midsole 10 that might cause discomfort to a user's footwhile wearing the footwear.

A compressible member 42 is placed on the upper surfaces 24 and 40 ofthe outsole 12 and adjustment member 32. The compressible member 42 ispreferably made of a resilient, foam or foam-based material such as EVAthat is designed to absorb impact during use of the footwear. Thecompressible member 42 is manufactured to have a designated hardness toabsorb such impact while also providing comfort to a user. The hardnessof the compressible member 42 is less than the hardness of the outsole12 to enhance the comfort of a user. In an embodiment, the compressiblemember 42 has a hardness of 48 to 52 asker C but may have any suitablehardness value. Also, the size and shape of the compressible member 42preferably corresponds to the size and shape of the upper surface 24 ofthe outsole 12. During use of the footwear, the compressible member 42compresses when one or more of the adjustable lugs 34 impact a hardsurface thereby allowing the adjustable lugs 34 to at least partiallyretract within the openings 22. On softer surfaces, the resilient,compressible member 42 expands and causes the adjustable lugs 34 to moveto an extended position thereby providing traction on those surfaces.

Referring now to FIGS. 4 and 5, the adjustable lugs 34 on the adjustmentmember 32 extend through the through holes 22 defined by the outsole 12so that the bottom surfaces of the adjustable lugs 34 are generallyparallel or in the same plane as the bottom surfaces of the fixed lugs16 on the outsole 12. As shown in FIG. 4, the compressible member 42 isseated on the adjustment member 32 to absorb contact from the adjustmentmember when the adjustable lugs 34 contact relatively hard surfaces.

When a user walks or runs on generally soft terrain, such as a dirttrail, a gravel trail or grass, the adjustable lugs 34 generally remainfully extended in an extended position shown in FIG. 4. When the groundcontacting surface 18 of the outsole 12 contacts a relatively hardsurface, e.g., pavement, or rough terrain (e.g., rocky, uneven ground)as shown in FIG. 5, the adjustable lugs 34 move to a retracted position(i.e., move at least partially within the through holes and away fromthe extended position). As the adjustable lugs 34 move upwardly withinthe through holes 22, the upper surface 40 of the adjustment member 32pushes upwardly against the compressible member 42 to compress thecompressible member as shown in FIG. 5. The compressible member 42serves as a shock absorber and provides resistance to the adjustmentmember 32 so that the adjustable lugs 34 only retract as needed based onthe terrain.

When a user returns to relatively soft terrain such as a trail or grass,the compressible member 42 expands and pushes against the upper surface40 of the adjustment member 32 to cause the adjustable lugs 34 to moveoutwardly through the through holes 22. The self-adjusting, adjustablelugs 34 of the adjustment member 32 thereby allow the footwear to adjustto different terrains, such as soft or hard surfaces, or rocky anduneven terrains. This enables the footwear to provide maximum tractionfor a runner or walker in any terrain to enhance the user's performanceas well as their safety so that they avoid injury due to a slip or fall.

Although the midsole 11 is shown being used with walking or runningfootwear, it should be appreciated that the midsole may be used with anytype of footwear including, but not limited to, shoes, sandals, slippersand boots.

While a particular embodiment of the present footwear has been describedherein, it will be appreciated by those skilled in the art that changesand modifications may be made thereto without departing from theinvention in its broader aspects.

1. An article of footwear comprising: an outsole including a pluralityof first traction members extending from said outsole, said outsoledefining a plurality of openings; a plurality of second traction membersextending through said openings in said outsole, said second tractionmembers configured to move between an extended position, wherein saidsecond traction members are fully extended in said openings, and aretracted position, wherein said second traction members are at leastpartially retracted within said openings; and a compressible memberpositioned adjacent to said plurality of second traction members andconfigured to compress when said second traction members move to saidretracted position.
 2. The article of footwear of claim 1, furthercomprising an adjustment member including said plurality of secondtraction members, said plurality of second traction members extendingfrom said adjustment member.
 3. The article of footwear of claim 2,wherein said plurality of second traction members are integrally formedwith said adjustment member.
 4. The article of footwear of claim 2,wherein an upper surface of said outsole defines a recess for receivingsaid adjustment member so that an upper surface of said adjustmentmember and said upper surface of said outsole are substantially flushwhen said adjustment member is inserted in said recess.
 5. The articleof footwear of claim 1, wherein said plurality of first traction membersand said plurality of said second traction members are adjacent to eachother.
 6. The article of footwear of claim 1, wherein said plurality offirst traction members are positioned on an outer portion of saidoutsole and said openings are located at an inner portion of saidoutsole so that said plurality of second traction members are at leastpartially surrounded by said plurality of first traction members whensaid plurality of second traction members extend through said openings.7. The article of footwear of claim 1, wherein said plurality of firsttraction members are integrally formed with said outsole.
 8. The articleof footwear of claim 1, wherein said outsole is made of an abrasionresistant material.
 9. The article of footwear of claim 1, wherein saidcompressible member is made of a material having a first hardness valueand said outsole is made of a material having a second hardness value,wherein said second hardness value is greater than said first hardnessvalue.
 10. The article of footwear of claim 1, wherein at least one ofsaid compressible member and said outsole is made of a foam material.11. A article of footwear comprising: an outsole including tractionmeans located on a perimeter of said outsole for providing traction onan underlying surface, and a plurality of openings on a central portionof said outsole; a plurality of adjustable lugs extending through andmovable within said openings; and adjustment means operatively connectedto said adjustable lugs for extending or retracting said lugs based onthe hardness of the underlying surface.
 12. The article of footwear ofclaim 11, wherein said adjustment means is made of a material having afirst hardness value and said outsole is made of a material having asecond hardness value, wherein said second hardness value is greaterthan said first hardness value.
 13. The article of footwear of claim 11,wherein at least one of said adjustment means and said outsole is madeof a foam material.
 14. The article of footwear of claim 11, whereinsaid outsole is made of an abrasion resistant material.
 15. An articleof footwear comprising: an outsole including a plurality of fixed lugsintegrally formed on at least a portion of a perimeter of a first sideof said outsole, said outsole defining a plurality of openings locatedat least partially within said plurality of lugs; a plurality ofadjustable lugs extending through said openings, said adjustable lugsbeing movable between an extended position and a retracted position; anda compressible member positioned adjacent to said plurality ofadjustable lugs on a second, opposing side of said outsole, saidplurality of adjustable lugs being in said extended position when saidcompressible member is not compressed, and said adjustable lugs being ina retracted position when said compressible member is compressed. 16.The article of footwear of claim 15, wherein said outsole is made of anabrasion resistant material.
 17. The article of footwear of claim 15,wherein said compressible member is made of a material having a firsthardness value and said outsole is made of a material having a secondhardness value, wherein said second hardness value is greater than saidfirst hardness value.
 18. The article of footwear of claim 15, whereinat least one of said compressible member and said outsole is made of afoam material.
 19. The article of footwear of claim 15, wherein saidfixed lugs and said adjustable lugs are made of different materials.